This invention relates to an improvement in power erasers. Conventionally, cylindrically shaped erasers are held with a collet having a plurality of longitudinal slots. The outer end of the collet is flared to retain a collar and the outer surface of the collet is tapered slightly thereby forming a frustum of a cone with the base of the cone toward the outer end of the collet. Movement of a collar, which surrounds the collet, toward the outer end of the collet causes an eraser placed within the collet to be squeezed and held in place for use. These conventional features are shown in FIG. 1.
The above described apparatus is satisfactory except for an annoying problem which occurs from time to time as the power eraser is used. Occasionally, the operator will allow the eraser to become worn to the point where it cannot be conveniently gripped with the fingers and additional eraser material extracted for continued use. At this time, the user is reduced to poking a pointed instrument, such as a pair of dividers into one of the slots and forcing more eraser material out of the collet. The invention described herein is a feeding mechanism which solves this problem by adding means for sliding the eraser outwardly by inserting prongs into the eraser and moving the prongs outwardly.
Several species of the means for sliding the eraser outwardly are shown in the accompaning drawings and will be discussed in detail in the following material.
The problem of feeding the eraser when it is worn down to the collet has been recognized before. The solutions shown in the following patents all address the problem, however, this invention is unique in that it provides a feeder mechanism of simple construction. Furthermore, this invention can be retrofitted onto the conventional power erasers in use today. See:
Motor Driven Adjustable Eraser, C. Sturzenegger, U.S. Pat. No. 2,487,903 PA0 Eraser Control Apparatus, N. L. Stokes, U.S. Pat. No. 3,427,677 PA0 Eraser Molding Chuck and Eraser, L. J. Misuraca, U.S. Pat. No. 3,224,417